Social weavers are small birds that live in communes, building joint nests for up to 300 pairs. The nests up can be as large as 25 feet wide, 5 feet high, weighing over one ton, and with an individual room for every couple. One known colony is over 100 years old.
Sometimes the trees they are in collapse and die from the weight.
Thanks to telephone poles, and power lines, the social weavers are expanding their range.
Twigs, coarse grass and straw are the main building materials. Nest interiors are lined with fur, feathers and soft plants. They offer a stable micro climate for hot days and cold nights in the Kalahari desert. The birds use them for sleeping as well as breeding.
They enter from the bottom.
Another sub-species of the weaver bird weaves intricate individual nests.
The best weaver birds have the ability to tie dozens of different shaped knots and loops for which they use their feet as well as beaks.
Designs and neatness of construction vary widely among the different species of weaver birds. Some are simple and scruffy, with a small tube and roundish nests. Other species build much more elaborate nests, with the strands of grass carefully interwoven to form a well-defined structure. The main part is a hollow sphere, lined with nesting material, accessed through a long tube which has a small entrance hole. The nests are usually tough and well-secured so a high wind will not blow them down.
1) First the male flaunts his brilliant blue feet with an exaggerated high-stepping silly-looking strut. Then they spread their wings and tilt their bills upwards while they whistle and groan (see below, including video).
2) The male presents nesting materials to the female like twigs and grass, but then she lays the eggs in a shallow depression on flat ground.
3) The female lacks the extra skin birds have to fold over eggs and keep them warm—So she uses her blue-webbed-feet which have extra blood flow to incubate them.
4) Once hatched, the female balances the chicks on top of her feet for one month while both parents feed them.